The present invention is directed to an electronic system for monitoring the coupling of a trailer to a trailer hitch assembly that is mounted on a truck chassis, and in particular is directed to an electronic system that indicates whether the trailer is properly coupled to the trailer hitch assembly by discriminating between components of the trailer, components of the hitch assembly and foreign materials.
Electronic coupling control systems for a vehicle trailer hitch assembly are described in each of U.S. Pat. No. 5,861,802, entitled “FIFTH WHEEL HITCH COUPLING CONTROL SYSTEM” to Hungerink et al. and U.S. Pat. Nos. 6,285,278 and 6,452,485, each entitled “ELECTRONIC SYSTEM FOR MONITORING A FIFTH WHEEL HITCH,” to Schutt et al. U.S. Pat. Nos. 5,861,802; 6,285,278 and 6,452,485 are each assigned to the assignee of the present invention and are hereby incorporated by reference in their entirety. Each of these patents disclose an electronic coupling control system that includes a trailer sensor for sensing when a trailer is located proximate the hitch assembly, a kingpin sensor for sensing the presence of a trailer kingpin in a hitch plate throat, and a lock sensor for sensing when the locking mechanism is locked in a secured position. These patents further disclose an indicator located within the vehicle for providing trailer hitch assembly coupling status information to a driver of a vehicle. A control circuit is coupled to the trailer sensor, the kingpin sensor, the lock sensor and the indicator. The sensors are utilized by the control circuit to inform a driver when a trailer is in close proximity to the trailer hitch assembly, when the trailer kingpin is positioned in the hitch throat and when the locking mechanism is in a locked position. The electronic coupling control system is also capable of performing various self-diagnostic routines to ensure proper operation of the system when the vehicle ignition is turned on.
Heretofore, systems like those described above typically incorporate contact-type sensors susceptible to degradation from the stringent environment within which these sensors are utilized, including degradation from normal use, extreme use such as experienced during some coupling operations, and the inclusion of foreign solids within the environment, such as grease, water and ice each laden with ferromagnetic materials. These ferromagnetic materials as laden within the grease, etc., can be the cause of “false-positive” readings as conveyed to the operator, or readings that falsely indicate proper alignment of the kingpin with respect to the throat of the hitch plate. Improper alignment of the kingpin with the throat of the hitch plate may potentially result in dropping a trailer from the associated vehicle either at a shipping dock, or potentially on a public roadway, with significant damage to the associated equipment and surrounding property, and further personal injury or worse.
An electronic system for monitoring the receiving of a kingpin of a trailer within a throat of a hitch plate is desired that accurately and reliably differentiates between the kingpin and foreign materials, thereby eliminating “false-positive” readings of proper alignment to the operator of an associated vehicle.